from the infomraiton given, what is the biggest flaw in the study? A pharmaceutical company conducted a study to test the effectiveness of a new anti-depression medication. 500 adults suffering from depression were selected at random and were randomly assigned to either a treatment group or a placebo group. The experiment was double blind. The results were analyzed by the company. a. confounding variables b. variables are difficult to define/measure c. selection bias d. the source of study e the setting may not encourage honest responses